1. Field of the Invention
The present invention relates to roaming of a portable terminal apparatus such as a portable telephone terminal, and to an information processing apparatus, a portable terminal apparatus, and a roaming information processing method thereof to obtain operator information from, for example, a mobile communication network (HPLMN: Home Public Land Mobile Network) and utilize the information for selecting an operator at a roaming destination.
2. Description of the Related Art
According to a conventional international roaming, when a portable terminal apparatus will have moved to the area of a roaming destination thereof, which operator will be available for communication is identified. It is not easy not only to select an operator but also to know whether roaming itself is possible depending on the destination before going abroad. When a plurality of operators are present at the roaming destination, obtaining information such as the contents of services thereof, etc., is indispensable in selecting an operator.
Methods of obtaining information such as a network operator, from a base station accessible from a portable terminal apparatus, include a method of setting priority of operators such as an operator that provided the last service, and an operator to which a user subscribed, an operator selected according to priority stored in a storing medium, an operator selected based on a received electric intensity (for example, Japanese Patent Application Laid-Open Publication No. 2002-218522). Similarly, for a portable terminal apparatus having a communicating function, a method has been proposed of notifying a user of communication conditions that minimize the cost for a communication route by collecting information on roaming connection in a foreign country from the provider to which a user subscribes (Japanese Patent Application Laid-Open Publication No. 2002-125066). A search scheme has been proposed of registering selection priority of a plurality of wireless communication systems to be used in a portable terminal apparatus and a wireless communication system to be used is selected according to the selection priority (Japanese Patent Application Laid-Open Publication No. 06-188830).
It is troublesome to grasp the contents of services of each operator such as charges and the area covering rates and to select an operator even if the operators at a roaming destination can be identified before moving. When the area covering rate and the quality of calls are lowered by selecting an operator, selecting the operator has no meaning though the calling charge can be minimized. The criteria for selecting an operator differ by user and are diverse. According to a scheme (Japanese Patent Application Laid-Open Publication No. 06-188830) of registering a communication network in advance into a portable terminal apparatus and selecting from the communication network an operator to be used according to priority, operators to be used are limited to those that are registered.
It is very beneficial to expand obtainable operator information before roaming and select a desired operator from the obtained operator information. However, none of Japanese Patent Application Laid-Open Publication No. 2002-218522, Japanese Patent Application Laid-Open Publication No. 2002-125066 and Japanese Patent Application Laid-Open Publication No. 06-188830 discloses such a task and includes suggestion about the solution of such a task. Though Japanese Patent Application Laid-Open Publication No. 06-188830 describes that the registered information is searched in advance, Japanese Patent Application Laid-Open Publication No. 06-188830 has no disclosure and no suggestion about collection of operator information to be registered.